using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
public class Test
{
public static void Main()
{
var input = "X1 OR ( X2 AND( X3 AND X4 ) AND X5 ) OR X6";
var filtered = Regex.Replace(input, @"\((?>[^()]|(?<o>)\(|(?<-o>)\))*\)(?(o)(?!))", string.Empty);
var result = filtered.Split(new[] { ' ' },
StringSplitOptions.RemoveEmptyEntries)
.Where(element => element == "OR" || element == "AND");
var temp = string.Join(" ", result);
Console.WriteLine(temp);
}
}
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